A sweeheart of an Angel Trumpet...

Actually it is a Sweetheart cross involving brugmansia Sweetheart x (Miss Caylie x Genevieve).  The picture below shows a bloom on the first day and by day 2 the green portion of the corolla tube became white. 

I have several single white seedlings from this cross in bloom right now.  They really put on a show when they flush.  I'm certain at least one of these will become a keeper by fall.